Nacelle inner flow structure leading edge latching system

ABSTRACT

A latch assembly for securing a nacelle portion of a gas turbine engine includes first and second nacelle flow structures that define a portion of a bypass flowpath. A seal is engageable between the first and second nacelle flow structures. A latch is rotatable about a pivot between latched and unlatched positions. The latch maintains the seal in engagement with the first and second nacelle flow structures in the latched position. A method of opening a nacelle flow structure includes the steps of pivoting a latch from a latched position to an unlatched position, and unlatching a first nacelle flow structure relative to a second nacelle flow structure in response to the latch pivoting step.

BACKGROUND

This disclosure relates to a nacelle for a gas turbine engine. Moreparticularly, the disclosure relates to a latching system configured toensure that the latch is able to disengage and release a portion of anacelle.

One type of gas turbine engine includes a core engine that drives a fanarranged in a bypass flowpath. The bypass flowpath is provided betweencore and fan nacelles, the core nacelle surrounds the core engine. Oneexample gas turbine engine includes a flow structure that provides innerand outer flow structures that define the bypass flowpath. The flowstructure provides portions of the fan and core nacelles along one axialportion of the engine.

The core nacelle encloses a core compartment that houses pressurizedconduits, such as compressed air ducts. While the bypass flow pressurein the bypass flowpath aids in maintaining the inner flow structure in aclosed and sealed position around the core flowpath, if a high pressureconduit bursts, the pressure within the core compartment may increaseand separate a leading edge of the inner flow structure from its matingstructure. In this condition, bypass flow may leak past the inner flowstructure into the core compartment, which may destroy and dislodgeportions of the core and fan nacelles.

To this end, latching assemblies have been proposed, which maintain theleading edge of the inner flow structure in a fully closed position. Thelatching assembly may be rather complex and may be susceptible tobecoming stuck, which requires surrounding structure to be disassembledand removed to gain access to the stuck latch.

SUMMARY

In one exemplary embodiment, a latch assembly for securing a nacelleportion of a gas turbine engine includes first and second nacelle flowstructures that define a portion of a bypass flowpath. A seal isengageable between the first and second nacelle flow structures. A latchis rotatable about a pivot between latched and unlatched positions. Thelatch maintains the seal in engagement with the first and second nacelleflow structures in the latched position.

In a further embodiment of any of the above, first and second reactionload brackets are affixed relative to the first and second nacelle flowstructures. One of the first and second reaction load brackets pivotallysupports the latch, and the other of the first and second reaction loadbrackets includes a tab cooperating with the latch in the latchedposition.

In a further embodiment of any of the above, the latch assembly includesa cable that is operatively connected to the latch and configured torotate the latch about the pivot.

In a further embodiment of any of the above, the latch assembly includesa bifurcation arranged in the bypass flowpath. The cable passes throughthe bifurcation.

In a further embodiment of any of the above, the latch assembly includesfirst and second drive elements that are respectively connected to thelatch and cable and are configured to transmit input from the cable tothe latch.

In a further embodiment of any of the above, the first and second driveelements are gears.

In a further embodiment of any of the above, the latch assembly includesa handle connected to the cable. The handle is configured to actuate thelatch through the cable.

In a further embodiment of any of the above, the latch assembly includesa coupling that operatively connects the handle to a pair of cables.Each cable unlatches a side having the first and second nacelle flowstructures.

In a further embodiment of any of the above, the second nacelle flowstructure is movable relative to the first nacelle flow structure abouta hinge. A second nacelle flow structure provides inner and outer flowstructures that define the bypass flowpath.

In a further embodiment of any of the above, the inner flow structureprovides a portion of the core nacelle enclosing a core compartmentabout a core engine.

In a further embodiment of any of the above, the latch assembly includesa compressed air duct arranged in the core compartment.

In a further embodiment of any of the above, the latch assembly includesa release member is operatively coupled to the latch to override aconventional latch releasing device.

In a further embodiment of any of the above, the latch assembly includesa tool that is removably received by the release member during anemergency latch releasing procedure.

In a further embodiment of any of the above, the latch assembly includesa thrust reverser. The thrust reverser is in an open position to receivethe tool in the bypass flowpath.

In another exemplary embodiment, a method of opening a nacelle flowstructure includes the steps of pivoting a latch from a latched positionto an unlatched position, and unlatching a first nacelle flow structurerelative to a second nacelle flow structure in response to the latchpivoting step.

In a further embodiment of any of the above, the method includes thestep of operating a handle operatively connected to the latch. The latchpivoting step is performed in response to the handle operating step.

In a further embodiment of any of the above, the method includes thestep of operating a release member with a tool subsequent to a failedattempt of a conventional latch releasing procedure.

In a further embodiment of any of the above, the conventional latchreleasing procedure includes operating a handle operatively connected tothe latch. The latch pivoting step is performed in response to thehandle operating step.

In a further embodiment of any of the above, the method includes thestep of actuating a thrust reverser to expose a bypass flowpath, andinserting the tool into the bypass flowpath to engage the releasemember.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be further understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a highly schematic view of an example gas turbine enginehaving an inner flow structure with a latch assembly.

FIG. 2 is a cross-sectional area of the gas turbine engine taken alongline 2-2 in FIG. 1 and under normal operating conditions.

FIG. 3 is a cross-sectional view similar to FIG. 2 during a highpressure core compartment event.

FIG. 4A is a cross-sectional view illustrating the inner flow structuresealed against a mating structure during normal operating conditions.

FIG. 4B illustrates the inner flow structure unseated from its matingstructure during a high pressure core compartment event shown in FIG. 3.

FIG. 5A illustrates the latch assembly in a latched position.

FIG. 5B illustrates the latch assembly in an unlatched position.

FIG. 6 illustrates a lower bifurcation with a handle and cable forlatching and unlatching the latch assembly.

FIG. 7 is a cross-sectional view through the lower bifurcation alongline 7-7 in FIG. 6.

FIG. 8A is a schematic view through a thrust reverser of the gas turbineengine, which provides access to a stuck latch assembly.

FIG. 8B is an enlarged view of the latch assembly illustrated in FIG.8A.

DETAILED DESCRIPTION

An example gas turbine engine 10 is schematically illustrated in FIG. 1.The engine 10 includes a core engine 12 receiving a core flow C at aninlet 14. The core flow C flows through the core engine 12 and isexpelled through an exhaust outlet 16 surrounding a tail cone 20.

The core engine 12 drives a fan 18 arranged in a bypass flowpath 23. Afan case 22 surrounds the fan 18 and provides structure for securing theengine 10 to a pylon 38 (FIG. 2). The fan case 22 is housed within a fannacelle 19. Multiple circumferentially spaced flow exit guide vanes 24may extend radially between the fan case 22 and the core engine 12 aftof the fan 18. In one example, the flow exit guide vanes 24 are hollowand may accommodate wires or fluid conduits.

A core nacelle 21 surrounds the core engine 12 and provides a corecompartment 30. Various components may be provided in the corecompartment 30, such as fluid conduits, for example, a compressed airduct 32. The compressed air duct 32 is under high pressure and maysupply compressed air from a low or high pressure compressor stage to ahigh pressure turbine stage for cooling, for example.

Upper and lower bifurcations 26, 27 may extend radially between the fanand core nacelles 19, 21 in locations opposite one another toaccommodate wires, fluid conduit or other components.

The bypass flowpath 23 is provided by inner and outer flow structures50, 51, which provide portions of the fan and core nacelles 19, 21 alongan axial portion of the engine 10. A thrust reverser 28 is arrangedoutwardly of the outer flow structures 51 in the fan nacelle 19. Theinner flow structure 50 is secured about the core compartment 30 with alatch assembly 36, which may be actuated by a handle 34 mounted outsidethe fan nacelle 19, for example. A cable 70 (FIGS. 6 and 7) may berouted from the handle 34 through one of the upper and lowerbifurcations 26, 27 to the latch assembly 36, for example. Additionally,latches may also be used and located as desired. The handle 34 providesa conventional latch releasing device for a conventional latch releasingprocedure.

Referring to FIG. 2, the inner and outer flow structures 50, 51, whichare integral with one another, are supported relative to the pylon 38 byhinges 40. Upper and lower bumpers 42, 44 support the inner structure 50relative to the upper and lower bifurcations 26, 27 in a desiredposition. During normal operation, as illustrated in FIG. 2, bypasspressure BP within the bypass flowpath 23 exerts a force on the innerflow structure 50 that maintains desired engagement with the upper andlower bumpers 42, 44. Referring to FIG. 3, an undesirably high corepressure CP may result from a ruptured pressurized fluid conduit, suchas the compressed air duct 32. As a result of such a high pressure corecompartment event, the inner flow structure 50 may become deformed, asillustrated on the left half of FIG. 3. During the event, either or bothleft and right side flow structures may deflect without the disclosedlatch.

Referring to FIG. 4A and 4B, the inner flow structure 50 supports a seal54 at a leading edge 52. The seal 54 engages a flange 48 of an enginefan case structure 46 with the inner flow structure 50 being flush withthe structure 46 during normal operation such that the structure 46 andinner flow structure 50 provide uninterrupted first and second nacelleflow structures. During an event in which an undesired core pressure CPis generated within the core compartment 30, the inner flow structure 50and seal 54 may be forced radially outward and out of engagement withthe flange 48, which permits bypass flow B in a bypass flowpath 23 toenter the core compartment 30. Such a condition may result in damage tothe core nacelle 21.

Referring to FIGS. 5A and 5B, the latch assembly 36 is arranged near theleading edge 52 prevent deflection of the inner flow structure 50 andmaintain the seal 54 in engagement with the flange 48 even if undesiredcore pressure CP exists. In one example, a first load reaction bracket56 is supported by the structure 46. A second load reaction bracket 58is mounted to the inner flow structure 50. The first load reactionbracket 56 includes a tab 60 that cooperates with a latch 62 pivotallymounted to the second load reaction bracket 58 to maintain the positionof the inner flow structure 50 when latched, shown in FIG. 5A. In oneexample, a first drive element 64 is connected to the latch 62. A seconddrive element 66 cooperates with the first drive element 64 and isoperably connected to the handle 34 (FIG. 1) for actuation of the latchassembly 36. In one example, the first and second drive elements 66, 68are gears that transmit input to the latch 62. FIG. 5B illustrates thelatch 62 in an open position in which the latch 62 is disengaged fromthe tab 60. Latch assembly 36 may use a different configuration of driveelements, if desired.

FIGS. 6 and 7 illustrate one example routing of cables 70interconnecting the handle 34 to the latch assembly 36. The cable 70rotates the latch 62 about its pivot. One cable 70 may be provided foreach half of the inner flow structure 50 provided on either side of theengine 10, illustrated in FIG. 2. The handle 34 may be positioned at thelower bifurcation 27. A coupling 68 mechanically interconnects thehandle 34 to cables 70, which are arranged within a cavity 72 of thelower bifurcation 27.

Alternatively or additionally, the latch 36 may be located in the aftsection of the core nacelle 21. The latches 136A-C may also be used tosecure the left and right halves of the flow structures to one another,as best shown in FIGS. 1 and 2.

In the event that the latch assembly 36 becomes stuck or a cable 70breaks, a release member 80 may cooperate with the latch assembly 36 torelease the latch 62 and override the conventional latch releasingprocedure and provide an emergency release of the latch 62. In oneexample, the thrust reverser 28 is actuated to expose the bypassflowpath 23 and the release member 80. With the thrust reverser 28actuated, the blocker doors 76 are disposed within the bypass flowpath23 and the cascade assembly 74 is exposed. A tool 78 may be passedthrough the cascade assembly 74 into the bypass flowpath 23 to engagethe release member 80. As illustrated in FIG. 8B, an end 84 of the tool78 may be received in a head 82 of the release member 80. The releasemember 80 may cooperate with one or more of the first and second driveelements 64, 66 to rotate the latch 62 out of engagement with the tab60. The illustration of the release member 80 is schematic.

Although an example embodiment has been disclosed, a worker of ordinaryskill in this art would recognize that certain modifications would comewithin the scope of the claims. For that reason, the following claimsshould be studied to determine their true scope and content.

What is claimed is:
 1. A latch assembly for securing a nacelle portionof a gas turbine engine comprising: first and second nacelle flowstructures defining a portion of a bypass flowpath; a seal engageablebetween the first and second nacelle flow structures; and a latchrotatable about a pivot between latched and unlatched positions, thelatch maintaining the seal in engagement with the first and secondnacelle flow structures in the latched position.
 2. The latch assemblyaccording to claim 1, wherein first and second reaction load bracketsare affixed relative to the first and second nacelle flow structures,one of the first and second reaction load brackets pivotally supportingthe latch, and the other of the first and second reaction load bracketsincluding a tab cooperating with the latch in the latched position. 3.The latch assembly according to claim 2, comprising a cable operativelyconnected to the latch and configured to rotate the latch about thepivot.
 4. The latch assembly according to claim 3, comprising abifurcation arranged in the bypass flowpath, the cable passing throughthe bifurcation.
 5. The latch assembly according to claim 3, comprisingfirst and second drive elements respectively connected to the latch andcable and configured to transmit input from the cable to the latch. 6.The latch assembly according to claim 5, wherein the first and seconddrive elements are gears.
 7. The latch assembly according to claim 3,comprising a handle connected to the cable, the handle configured toactuate the latch through the cable.
 8. The latch assembly according toclaim 7, comprising a coupling operatively connecting the handle to apair of cables, each cable unlatching a side having the first and secondnacelle flow structures.
 9. The latch assembly according to claim 1,wherein the second nacelle flow structure is movable relative to thefirst nacelle flow structure about a hinge, second nacelle flowstructure providing inner and outer flow structures defining the bypassflowpath.
 10. The latch assembly according to claim 9, wherein the innerflow structure provides a portion of the core nacelle enclosing a corecompartment about a core engine.
 11. The latch assembly according toclaim 10, comprising a compressed air duct arranged in the corecompartment.
 12. The latch assembly according to claim 1, comprising arelease member operatively coupled to the latch to override aconventional latch releasing device.
 13. The latch assembly according toclaim 12, comprising a tool removably received by the release memberduring an emergency latch releasing procedure.
 14. The latch assemblyaccording to claim 13, comprising a thrust reverser, the thrust reverserin an open position to receive the tool in the bypass flowpath.
 15. Amethod of opening a nacelle flow structure comprising the steps of:pivoting a latch from a latched position to an unlatched position; andunlatching a first nacelle flow structure relative to a second nacelleflow structure in response to the latch pivoting step.
 16. The methodaccording to claim 15, comprising the step of operating a handleoperatively connected to the latch, the latch pivoting step performed inresponse to the handle operating step.
 17. The method according to claim15, comprising the step of operating a release member with a toolsubsequent to a failed attempt of a conventional latch releasingprocedure.
 18. The method according to claim 17, wherein theconventional latch releasing procedure includes operating a handleoperatively connected to the latch, the latch pivoting step performed inresponse to the handle operating step.
 19. The method according to claim17, comprising the step of actuating a thrust reverser to expose abypass flowpath, and inserting the tool into the bypass flowpath toengage the release member.